1. Field
Apparatuses and methods consistent with the exemplary embodiments relate to an image forming apparatus and an auto color registration method of the same, and more particularly, to an image forming apparatus and an auto color registration method of the same which prints a color image by single pass.
2. Description of the Related Art
In general, an electrophotographic image forming apparatus forms an electrostatic latent image on an image carrier charged by a predetermined electric potential, by exposing light thereto, develops the image with a developer in a predetermined color and transfers to a print medium and fuses the image. The electrophotographic image forming apparatus may be classified into a mono type and a color type according to a color realization. The color image forming apparatus may be classified further into a single pass type and a multi pass type according to a transfer method for images in each color.
The single-pass color image forming apparatus includes a plurality of developers corresponding to each color, e.g., developers corresponding to each of yellow (Y), magenta (M), cyan (C) and black (K) colors; and light scanning units corresponding to the developers to thereby overlap an image formed on the developers by single pass for realization of a color image. The realization of the color image requires an auto color registration (hereinafter, to be called the “ACR”) which registers an image in each color developed by the developers, in a correct location.
As shown in FIG. 1, the single-pass color image forming apparatus forms an ACR pattern 11 in each of the colors Y, M, C and K on a transfer belt 10 by using a developer, and detects the ACR pattern 11 through an ACR detector 15 to thereby perform the ACR. The ACR pattern 11 in each color includes a first ACR pattern 11a and a second ACR pattern 11b inclined to the first ACR pattern 11a to identify any error in the ACR in a width direction of the transfer belt 10.
The ACR pattern 11 is provided in at least two locations in the width direction of the transfer belt 10. In such a case, the ACR detector 15 includes a plurality of detectors 15a and 15b to detect an error of the ACR with respect to the ACR pattern 11 provided in the width direction of the transfer belt 10.
If an ACR pattern is printed on the transfer belt 10 for the performance of the ACR, such ACR pattern may be distorted by a defect of a surface of the transfer belt 10. Then, the ACR detector 15 may detect the distorted ACR pattern, leading to a distortion of the ACR.
To prevent the foregoing problem, in the conventional image forming apparatus, the ACR detector 15 detects any error from the surface of the transfer belt 10 at idle when the ACR pattern is not printed thereon and reflects such detection result to printing the ACR pattern.
However, in the conventional image forming apparatus, when the transfer belt without the image printed thereto idles, a friction force between the transfer belt and a cleaning blade (not shown) cleaning a remaining developer from the transfer belt becomes higher and may turn over the cleaning blade. If a predetermined pattern is printed on the transfer belt at idle to prevent the turn-over of the cleaning blade, the surface of the transfer belt having the printed pattern thereon is not detected normally and the defect from the surface is not detected nor adjusted.
In the foregoing method, the transfer belt idles to detect the defect thereof and thus the ACR time increases as much as the idle time.
In another conventional method, an additional adjustment algorithm is used to adjust such defect based on ACR data without the process of detecting the defect from the surface of the transfer belt 10. In this case, accuracy of the adjustment deteriorates as the detection of the surface of the transfer belt 10 is not performed.